The invention relates to speed regulating systems and more particularly to speed regulating systems for engine-driven vehicles, such as road vehicles, and especially such systems which are intended to regulate the maximum speed at which the vehicle can be driven by its engine.
Speed regulating systems are known which compare the actual vehicle speed with a pre-set value thereof and shut off or reduce the engine power when the vehicle exceeds the pre-set speed. Such systems may be used in commercial vehicles, such as trucks, to prevent overspeeding and resultant damage to the vehicle or its engine, and/or for fuel economy purposes.
A disadvantage of known systems, however, is that they prevent use being made of the kinetic energy gained by a vehicle as it runs downhill. The effect of the vehicle exceeding the pre-set speed on a downhill road is of course a shut-off of engine power--although the vehicle speed will nevertheless continue to increase because of gravity. When the road becomes level, or possibly uphill, the vehicle speed begins to fall and engine power will not be increased until the speed has fallen below the pre-set maximum. Therefore, the kinetic energy gained by the vehicle running downhill is lost or wasted, with consequent waste of fuel.
An object of the invention, therefore, is to provide an improved vehicle speed regulating system.
A more specific object of the invention is to provide a vehicle speed regulating system which enables use to be made of the kinetic energy gained by a vehicle is running downhill.